This invention concerns a hearing aid implant mounted in the ear according to the preamble to claim 1 and a hearing aid implant according to the one in claim 16.
If the organs in the ear that mechanically transmit vibrations are damaged and the transmission from the ear drum via hammer, anvil and stirrup no longer works on the oval window as it can in a person with normal hearing, the mechanical vibrations are purposely forced to work on one or more of the organs mentioned with the type of implants mentioned, corresponding to auditory signals received by a microphone arrangement in or outside the auditory canal. Even when there is inner ear damage, such implants are used: in that case, the mechanical vibrations on the oval window are amplified compared to normal hearing or altered in their frequency spectrum. This attempts to achieve the most optimal compensation for the inner ear damage. It is also conceivable for people basically even with normal hearing to wear an implant, especially when the application procedure is only minimal. Then audio signals from electric audio sources, like for example the Internet, MP3 players, CD players or conductive systems could be fed directly to the individual and finally to the implant as electrical signals. Also, predetermined desired hearing characteristics, like directional characteristics, can be made adjustable preferably on site with implants and microphones at the entrance to the ear, for both those with normal hearing and those with impaired hearing.
Thus, for example, it is known from U.S. Pat. No. 5,800,339 how to couple the type of implant mentioned to one of the organs mentioned in the middle ear. The implant consists of two masses that can move in relation to one another. The lighter of the two masses is connected to the organ, for example, one of the ossicles, while the second floats. The two masses are set in vibration electrically in relation to one another, corresponding to acoustic signals received. According to U.S. Pat. No. 5,558,618, it is known with an implant of the type mentioned above mounted in the ear how to mount a small permanent magnetic plate on one of the organs mentioned, especially on one of the ossicles, and to excite it mechanically without contact by a coil mounted directly in the ossicle area. One form of embodiment proposes building a microphone, a manually activated switching organ, batteries, amplifier and coil into a housing and putting it in the auditory canal in such a way that the coil is in turn adjacent to the area of a middle ear organ, especially like an ossicle, namely the hammer, to be set in vibration. This procedure requires the insertion of a relatively voluminous apparatus in the auditory canal, which is prepared accordingly and cleared up to the middle ear.
U.S. Pat. No. 5,906,635 also proposes providing a permanent magnetic disk on an ossicle and exciting vibrations via a coil mounted without contact in its direct area.
These implants that work on organs in the middle ear have the major disadvantage that they require extensive surgical procedures in the middle ear area itself and in the transitional area from the outer ear to the middle ear, i.e., in the stirrup area, to adapt the respective areas to the specifically selected implant techniques. Often a change from one implant technique to another is highly problematic, because outer and middle ear areas must be specifically adapted to the implant technique installed previously.
The problem of the invention is to propose a hearing aid implant of the type mentioned above mounted in the ear in which the application area, i.e., the outer and middle ear, is adapted only minimally invasively.
This is achieved on the above-mentioned type of hearing aid implant mounted in the ear by attaching the housing to the outer part of the ear in the stirrup area and having the end of the actuator facing away from the housing work in the middle ear.
This makes it possible to work from the outer ear area, through the stirrup area and finally into the middle ear with only a small passage to place housings with drive transducers in the outer ear area. The application procedure is normally done through the auditory canal. Because of the volume of the auditory canal and the simple surgical accessibility of the auditory canal wall area, this makes insertion of the housing with the drive transducer in it simple and minimally invasive. Also the actuator can be placed in the middle ear with only a minimal procedure, i.e., there are practically no implant-specific surgical adjustments to be made. This also makes it possible to change it or exchange it for another implant product.
In another preferred form of embodiment, the housing is mounted directly on the wall of the auditory canal or right next to it in the tissue of the wall of the auditory canal.
Although it is certainly possible to couple the end of the actuator mentioned anywhere in the middle ear anywhere effectively where mechanical vibrations ultimately affect the inner ear through the oval window, one preferred form of embodiment proposes anchoring the end of the actuator mentioned on one of the ossicles, either by a clip on the end of the actuator or by another known coupling technique that permits perfect transmission of vibrations to the respective ossicle.
In another preferred embodiment of the hearing aid implant mounted in the ear, the electromechanical drive transducer has an electrical input stage, which is attached to the housing. This has the advantage that electrical connecting lines from an acoustic-electrical transducer, which is not the subject of the invention, for example mounted outside the ear, are mechanically stationary. This bypasses the problem of stress changing these types of extremely thin electrical lines, and hence secondary acoustic interference signals caused by such mechanical vibrations as well.
Although in the following basically all known principles, if they are suitable by structural size, can be used as electromechanical drive transducers, like for example electrodynamic drive transducers, in the form of embodiment preferred today, the electromechanical drive transducer is designed as an electromagnetic or, if necessary, a piezoelectric drive transducer. These allow an extremely small structural design, which also allows it to be built like a little rod along an axis. This is an extremely good shape for insertion into the auditory canal wall or the tissue surrounding the auditory canal. Accordingly, the housing is preferably designed as a small tube and has an aperture on at least one of its front sides, from which the actuator goes out into the middle ear.
When the preferred electromechanical transducer is made as an electromagnetic drive transducer, preferably there is a coil arrangement stationary on the housing, and the actuator is mounted on a sliding bearing with a permanent magnetic part in the coil. Neodymium can be used, for example, as the permanent magnet material; this makes it possible to build extremely strong permanent magnets with low structural volume, for example Ndxe2x80x94Fexe2x80x94B material.
In another preferred form of embodiment, the electrical input lines into the implant or its electromechanical drive transducer go along the auditory canal walls or into the tissue or bone bordering the auditory canal.
In another preferred form of embodiment of the implant in the invention, its actuator is spring-mounted in relation to the housing.
In another preferred embodiment, the housing, in its tube-shaped design mentioned with the actuator coming out of an aperture on the front, has a part tapering off in diameter toward the aperture mentioned. This makes it possible, in this tiny diameter part to move the actuator as far as possible mechanically toward its end mentioned, but still build this part, not needed for insertion of the electromechanical transducer, with minimal volume.
In another preferred embodiment, the housing is also designed to be tubular in shape, preferably as a rotational body, i.e., basically cylindrical, if necessary with steadily conically tapering parts.
It is also possible, in one preferred embodiment, to provide anchoring organs like ribs or nap on the housing to anchor it in the body tissue or bone material. No. 1 shows the length of the implant in the direction of transmission between the working end of the actuator, on one hand, and the end of the housing facing away from that end, so it preferably lies in the range of:
8 mmxe2x89xa61xe2x89xa630 mm, preferably in the range of
8 mmxe2x89xa61xe2x89xa615 mm,
typically approximately 13 mm.
Preferably, the maximum diameter of the housing D is preferably chosen as follows:
2 mmxe2x89xa6Dxe2x89xa66 mm, preferably in the range of
2 mmxe2x89xa6Dxe2x89xa64 mm,
typically approximately 3 mm.
The hearing aid implant in the invention in itself is characterized, to solve the above-mentioned problem, by the wording in claim 16, with preferred embodiments in claims 17 to 21.